HST Demand Forecast Accuracy: Error, Bias and Worst Miss, 6 October to 5 November 2026

The day-ahead demand forecast for HST was off by 5.9% on average (mean absolute percentage error) over 719 hours from 6 October to 5 November 2026, and 59% of hours landed within 5% of the reading. Its bias was +1.3%: it ran high on average, an over forecast. The largest miss was 71 MW (46.7%) too low at 9 Oct 2026, 09:00 EDT (UTC-04:00). Dates and times are local (America/New_York).

Key Facts

The day-ahead demand forecast for HST was off by 5.9% on average (mean absolute percentage error) over 719 hours from 6 October to 5 November 2026, and 59% of hours landed within 5% of the reading. Its bias was +1.3%: it ran high on average, an over forecast. The largest miss was 71 MW (46.7%) too low at 9 Oct 2026, 09:00 EDT (UTC-04:00).
Across 53 US grids ranked by average error over their own latest 30 day windows, HST came 37 (1 is the smallest error).
On average the forecast differed from reported demand by 5 MW, against average demand of 80 MW.
The forecast was above reported demand in 54% of compared hours.

Forecast Error at a Glance

719 hours from 6 October to 5 November 2026

Average error5.9%

Bias+1.3%

Hours within 5%59%

Worst miss71 MW

Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (+1 MW per hour on average): the forecast ran high on average, an over forecast. The worst miss was 71 MW (46.7%) too low at 9 Oct 2026, 09:00 EDT (UTC-04:00): forecast 81 MW, reported 152 MW.

Source: U.S. Energy Information Administration (EIA). (US Government work, public domain) Data as of 2026-11-05. Accuracy is computed by World Power Monitor from the operator's hourly forecast and reported demand.

Forecast and Reported Demand, Last 7 Days

Local time, to 5 Nov 2026, 08:00 EST (UTC-05:00)

Hourly reported demand and the day-ahead forecast for HST over the last 7 days of the window, to 5 Nov 2026, 08:00 EST (UTC-05:00). Gaps are hours with a missing, zero or implausible report.

Data to 2026-11-05

Show the data table (168 rows)

Local hour	Reported demand	Day-ahead forecast
29 Oct, 10:00	75 MW	72 MW
29 Oct, 11:00	82 MW	77 MW
29 Oct, 12:00	89 MW	84 MW
29 Oct, 13:00	94 MW	88 MW
29 Oct, 14:00	99 MW	92 MW
29 Oct, 15:00	102 MW	97 MW
29 Oct, 16:00	102 MW	101 MW
29 Oct, 17:00	102 MW	102 MW
29 Oct, 18:00	101 MW	101 MW
29 Oct, 19:00	103 MW	103 MW
29 Oct, 20:00	100 MW	100 MW
29 Oct, 21:00	95 MW	95 MW
29 Oct, 22:00	87 MW	89 MW
29 Oct, 23:00	79 MW	82 MW
30 Oct, 00:00	71 MW	72 MW
30 Oct, 01:00	65 MW	65 MW
30 Oct, 02:00	61 MW	62 MW
30 Oct, 03:00	59 MW	58 MW
30 Oct, 04:00	59 MW	59 MW
30 Oct, 05:00	61 MW	60 MW
30 Oct, 06:00	63 MW	63 MW
30 Oct, 07:00	61 MW	61 MW
30 Oct, 08:00	62 MW	63 MW
30 Oct, 09:00	66 MW	69 MW
30 Oct, 10:00	76 MW	76 MW
30 Oct, 11:00	85 MW	83 MW
30 Oct, 12:00	91 MW	96 MW
30 Oct, 13:00	98 MW	96 MW
30 Oct, 14:00	100 MW	103 MW
30 Oct, 15:00	104 MW	103 MW
30 Oct, 16:00	107 MW	103 MW
30 Oct, 17:00	105 MW	102 MW
30 Oct, 18:00	101 MW	104 MW
30 Oct, 19:00	101 MW	101 MW
30 Oct, 20:00	97 MW	98 MW
30 Oct, 21:00	92 MW	91 MW
30 Oct, 22:00	87 MW	89 MW
30 Oct, 23:00	82 MW	82 MW
31 Oct, 00:00	77 MW	72 MW
31 Oct, 01:00	71 MW	66 MW
31 Oct, 02:00	69 MW	72 MW
31 Oct, 03:00	66 MW	70 MW
31 Oct, 04:00	64 MW	68 MW
31 Oct, 05:00	64 MW	72 MW
31 Oct, 06:00	65 MW	73 MW
31 Oct, 07:00	64 MW	67 MW
31 Oct, 08:00	69 MW	63 MW
31 Oct, 09:00	77 MW	68 MW
31 Oct, 10:00	85 MW	77 MW
31 Oct, 11:00	91 MW	85 MW
31 Oct, 12:00	98 MW	94 MW
31 Oct, 13:00	101 MW	98 MW
31 Oct, 14:00	102 MW	102 MW
31 Oct, 15:00	102 MW	105 MW
31 Oct, 16:00	102 MW	108 MW
31 Oct, 17:00	100 MW	107 MW
31 Oct, 18:00	96 MW	102 MW
31 Oct, 19:00	93 MW	102 MW
31 Oct, 20:00	89 MW	95 MW
31 Oct, 21:00	87 MW	91 MW
31 Oct, 22:00	85 MW	86 MW
31 Oct, 23:00	83 MW	78 MW
1 Nov, 00:00	78 MW	79 MW
1 Nov, 01:00	73 MW	66 MW
1 Nov, 01:00	68 MW	72 MW
1 Nov, 02:00	65 MW	69 MW
1 Nov, 03:00	64 MW	67 MW
1 Nov, 04:00	63 MW	67 MW
1 Nov, 05:00	64 MW	67 MW
1 Nov, 06:00	63 MW	69 MW
1 Nov, 07:00	66 MW	65 MW
1 Nov, 08:00	69 MW	70 MW
1 Nov, 09:00	71 MW	77 MW
1 Nov, 10:00	72 MW	86 MW
1 Nov, 11:00	72 MW	93 MW
1 Nov, 12:00	71 MW	99 MW
1 Nov, 13:00	71 MW	102 MW
1 Nov, 14:00	70 MW	104 MW
1 Nov, 15:00	72 MW	103 MW
1 Nov, 16:00	74 MW	103 MW
1 Nov, 17:00	77 MW	101 MW
1 Nov, 18:00	81 MW	98 MW
1 Nov, 19:00	80 MW	93 MW
1 Nov, 20:00	79 MW	90 MW
1 Nov, 21:00	77 MW	88 MW
1 Nov, 22:00	74 MW	86 MW
1 Nov, 23:00	69 MW	82 MW
2 Nov, 00:00	63 MW	69 MW
2 Nov, 01:00	59 MW	60 MW
2 Nov, 02:00	57 MW	56 MW
2 Nov, 03:00	55 MW	56 MW
2 Nov, 04:00	55 MW	55 MW
2 Nov, 05:00	58 MW	55 MW
2 Nov, 06:00	61 MW	58 MW
2 Nov, 07:00	61 MW	62 MW
2 Nov, 08:00	66 MW	66 MW
2 Nov, 09:00	73 MW	71 MW
2 Nov, 10:00	78 MW	72 MW
2 Nov, 11:00	83 MW	72 MW
2 Nov, 12:00	84 MW	71 MW
2 Nov, 13:00	83 MW	65 MW
2 Nov, 14:00	81 MW	68 MW
2 Nov, 15:00	76 MW	77 MW
2 Nov, 16:00	75 MW	77 MW
2 Nov, 17:00	78 MW	76 MW
2 Nov, 18:00	83 MW	77 MW
2 Nov, 19:00	81 MW	77 MW
2 Nov, 20:00	81 MW	75 MW
2 Nov, 21:00	77 MW	73 MW
2 Nov, 22:00	71 MW	68 MW
2 Nov, 23:00	65 MW	64 MW
3 Nov, 00:00	60 MW	64 MW
3 Nov, 01:00	57 MW	60 MW
3 Nov, 02:00	56 MW	58 MW
3 Nov, 03:00	55 MW	56 MW
3 Nov, 04:00	56 MW	57 MW
3 Nov, 05:00	58 MW	58 MW
3 Nov, 06:00	59 MW	62 MW
3 Nov, 07:00	60 MW	64 MW
3 Nov, 08:00	65 MW	65 MW
3 Nov, 09:00	73 MW	73 MW
3 Nov, 10:00	80 MW	79 MW
3 Nov, 11:00	86 MW	81 MW
3 Nov, 12:00	90 MW	84 MW
3 Nov, 13:00	91 MW	82 MW
3 Nov, 14:00	92 MW	78 MW
3 Nov, 15:00	94 MW	77 MW
3 Nov, 16:00	93 MW	72 MW
3 Nov, 17:00	95 MW	70 MW
3 Nov, 18:00	100 MW	80 MW
3 Nov, 19:00	99 MW	82 MW
3 Nov, 20:00	96 MW	81 MW
3 Nov, 21:00	91 MW	78 MW
3 Nov, 22:00	84 MW	76 MW
3 Nov, 23:00	77 MW	70 MW
4 Nov, 00:00	70 MW	73 MW
4 Nov, 01:00	65 MW	69 MW
4 Nov, 02:00	63 MW	67 MW
4 Nov, 03:00	62 MW	66 MW
4 Nov, 04:00	61 MW	66 MW
4 Nov, 05:00	64 MW	67 MW
4 Nov, 06:00	65 MW	69 MW
4 Nov, 07:00	62 MW	69 MW
4 Nov, 08:00	62 MW	73 MW
4 Nov, 09:00	65 MW	79 MW
4 Nov, 10:00	65 MW	85 MW
4 Nov, 11:00	67 MW	91 MW
4 Nov, 12:00	69 MW	94 MW
4 Nov, 13:00	73 MW	95 MW
4 Nov, 14:00	79 MW	91 MW
4 Nov, 15:00	82 MW	94 MW
4 Nov, 16:00	84 MW	91 MW
4 Nov, 17:00	86 MW	93 MW
4 Nov, 18:00	90 MW	97 MW
4 Nov, 19:00	89 MW	102 MW
4 Nov, 20:00	87 MW	100 MW
4 Nov, 21:00	83 MW	94 MW
4 Nov, 22:00	75 MW	90 MW
4 Nov, 23:00	68 MW	82 MW
5 Nov, 00:00	61 MW	65 MW
5 Nov, 01:00	57 MW	56 MW
5 Nov, 02:00	53 MW	54 MW
5 Nov, 03:00	52 MW	53 MW
5 Nov, 04:00	53 MW	53 MW
5 Nov, 05:00	55 MW	55 MW
5 Nov, 06:00	57 MW	56 MW
5 Nov, 07:00	58 MW	60 MW
5 Nov, 08:00	63 MW	60 MW

Assumptions

Only hours with both a forecast and a positive demand reading count (719 of 720 hours in the window). Missing and zero values, and readings under 30% or over 3 times the grid's own median for the window, are treated as reporting faults and left out.
Error is (forecast minus reported demand) divided by reported demand; average error uses absolute values so high and low misses do not cancel. Bias keeps the sign and does cancel.
Reported demand is preliminary and may be revised. A 30 day window is a short sample and one heat wave or holiday can move these figures.
US figures are for the EIA balancing authority or region named on this page. US and European grids are ranked separately.

Cite this page

APA 7

World Power Monitor. (2026). HST Demand Forecast Accuracy: Error, Bias and Worst Miss. https://worldpowermonitor.com/forecast-accuracy/hst/

Plain text

World Power Monitor. HST Demand Forecast Accuracy: Error, Bias and Worst Miss. Data as of 2026-11-05. Data from U.S. Energy Information Administration. https://worldpowermonitor.com/forecast-accuracy/hst/

BibTeX

@misc{wpm_forecast_accuracy_hst_2026,
  title = {{HST Demand Forecast Accuracy: Error, Bias and Worst Miss}},
  author = {{World Power Monitor}},
  year = {2026},
  note = {Data as of 2026-11-05. Data from U.S. Energy Information Administration.},
  url = {https://worldpowermonitor.com/forecast-accuracy/hst/}
}

Permalink: https://worldpowermonitor.com/forecast-accuracy/hst/

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HST Demand Forecast Accuracy: Error, Bias and Worst Miss, 6 October to 5 November 2026

Key Facts

Forecast Error at a Glance

Forecast and Reported Demand, Last 7 Days

Assumptions

Related